1/*
  2 * dma-fence-array: aggregate fences to be waited together
  3 *
  4 * Copyright (C) 2016 Collabora Ltd
  5 * Copyright (C) 2016 Advanced Micro Devices, Inc.
  6 * Authors:
  7 *	Gustavo Padovan <gustavo@padovan.org>
  8 *	Christian König <christian.koenig@amd.com>
  9 *
 10 * This program is free software; you can redistribute it and/or modify it
 11 * under the terms of the GNU General Public License version 2 as published by
 12 * the Free Software Foundation.
 13 *
 14 * This program is distributed in the hope that it will be useful, but WITHOUT
 15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 16 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 17 * more details.
 18 */
 19
 20#include <linux/export.h>
 21#include <linux/slab.h>
 22#include <linux/dma-fence-array.h>
 23
 24static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
 25{
 26	return "dma_fence_array";
 27}
 28
 29static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
 30{
 31	return "unbound";
 32}
 33
 34static void irq_dma_fence_array_work(struct irq_work *wrk)
 35{
 36	struct dma_fence_array *array = container_of(wrk, typeof(*array), work);
 37
 38	dma_fence_signal(&array->base);
 39	dma_fence_put(&array->base);
 40}
 41
 42static void dma_fence_array_cb_func(struct dma_fence *f,
 43				    struct dma_fence_cb *cb)
 44{
 45	struct dma_fence_array_cb *array_cb =
 46		container_of(cb, struct dma_fence_array_cb, cb);
 47	struct dma_fence_array *array = array_cb->array;
 48
 49	if (atomic_dec_and_test(&array->num_pending))
 50		irq_work_queue(&array->work);
 51	else
 52		dma_fence_put(&array->base);
 53}
 54
 55static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
 56{
 57	struct dma_fence_array *array = to_dma_fence_array(fence);
 58	struct dma_fence_array_cb *cb = (void *)(&array[1]);
 59	unsigned i;
 60
 61	for (i = 0; i < array->num_fences; ++i) {
 62		cb[i].array = array;
 63		/*
 64		 * As we may report that the fence is signaled before all
 65		 * callbacks are complete, we need to take an additional
 66		 * reference count on the array so that we do not free it too
 67		 * early. The core fence handling will only hold the reference
 68		 * until we signal the array as complete (but that is now
 69		 * insufficient).
 70		 */
 71		dma_fence_get(&array->base);
 72		if (dma_fence_add_callback(array->fences[i], &cb[i].cb,
 73					   dma_fence_array_cb_func)) {
 74			dma_fence_put(&array->base);
 75			if (atomic_dec_and_test(&array->num_pending))
 76				return false;
 77		}
 78	}
 79
 80	return true;
 81}
 82
 83static bool dma_fence_array_signaled(struct dma_fence *fence)
 84{
 85	struct dma_fence_array *array = to_dma_fence_array(fence);
 86
 87	return atomic_read(&array->num_pending) <= 0;
 88}
 89
 90static void dma_fence_array_release(struct dma_fence *fence)
 91{
 92	struct dma_fence_array *array = to_dma_fence_array(fence);
 93	unsigned i;
 94
 95	for (i = 0; i < array->num_fences; ++i)
 96		dma_fence_put(array->fences[i]);
 97
 98	kfree(array->fences);
 99	dma_fence_free(fence);
100}
101
102const struct dma_fence_ops dma_fence_array_ops = {
103	.get_driver_name = dma_fence_array_get_driver_name,
104	.get_timeline_name = dma_fence_array_get_timeline_name,
105	.enable_signaling = dma_fence_array_enable_signaling,
106	.signaled = dma_fence_array_signaled,
107	.wait = dma_fence_default_wait,
108	.release = dma_fence_array_release,
109};
110EXPORT_SYMBOL(dma_fence_array_ops);
111
112/**
113 * dma_fence_array_create - Create a custom fence array
114 * @num_fences:		[in]	number of fences to add in the array
115 * @fences:		[in]	array containing the fences
116 * @context:		[in]	fence context to use
117 * @seqno:		[in]	sequence number to use
118 * @signal_on_any:	[in]	signal on any fence in the array
119 *
120 * Allocate a dma_fence_array object and initialize the base fence with
121 * dma_fence_init().
122 * In case of error it returns NULL.
123 *
124 * The caller should allocate the fences array with num_fences size
125 * and fill it with the fences it wants to add to the object. Ownership of this
126 * array is taken and dma_fence_put() is used on each fence on release.
127 *
128 * If @signal_on_any is true the fence array signals if any fence in the array
129 * signals, otherwise it signals when all fences in the array signal.
130 */
131struct dma_fence_array *dma_fence_array_create(int num_fences,
132					       struct dma_fence **fences,
133					       u64 context, unsigned seqno,
134					       bool signal_on_any)
135{
136	struct dma_fence_array *array;
137	size_t size = sizeof(*array);
138
139	/* Allocate the callback structures behind the array. */
140	size += num_fences * sizeof(struct dma_fence_array_cb);
141	array = kzalloc(size, GFP_KERNEL);
142	if (!array)
143		return NULL;
144
145	spin_lock_init(&array->lock);
146	dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock,
147		       context, seqno);
148	init_irq_work(&array->work, irq_dma_fence_array_work);
149
150	array->num_fences = num_fences;
151	atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
152	array->fences = fences;
153
154	return array;
155}
156EXPORT_SYMBOL(dma_fence_array_create);
157
158/**
159 * dma_fence_match_context - Check if all fences are from the given context
160 * @fence:		[in]	fence or fence array
161 * @context:		[in]	fence context to check all fences against
162 *
163 * Checks the provided fence or, for a fence array, all fences in the array
164 * against the given context. Returns false if any fence is from a different
165 * context.
166 */
167bool dma_fence_match_context(struct dma_fence *fence, u64 context)
168{
169	struct dma_fence_array *array = to_dma_fence_array(fence);
170	unsigned i;
171
172	if (!dma_fence_is_array(fence))
173		return fence->context == context;
174
175	for (i = 0; i < array->num_fences; i++) {
176		if (array->fences[i]->context != context)
177			return false;
178	}
179
180	return true;
181}
182EXPORT_SYMBOL(dma_fence_match_context);